Patents by Inventor Da-Shan Shiu

Da-Shan Shiu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7420947
    Abstract: A method and apparatus for using information about a mobile terminal's location relative to a base station can improve performance of a communication system. In addition, information about the mobile terminal's velocity relative to the base station may be used to improve performance of the communication system. The location information may be used to estimate a nominal PN offset, and a set of PN offset to use, for processing communication signals. The velocity information may be used to estimate a nominal frequency of the communication signals.
    Type: Grant
    Filed: August 28, 2003
    Date of Patent: September 2, 2008
    Assignee: Qualcomm Incorporated
    Inventors: Andrew Sendonaris, Da-Shan Shiu, David Patterson, Pavathanathan Subrahmanya, Daisuke Terasawa
  • Publication number: 20080130731
    Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies.
    Type: Application
    Filed: July 23, 2007
    Publication date: June 5, 2008
    Inventors: Da-shan Shiu, Durga P. Malladi, Srikrishna Bhashyam
  • Patent number: 7376438
    Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.
    Type: Grant
    Filed: October 12, 2005
    Date of Patent: May 20, 2008
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Serge Willenegger, Richard Chi, Parvathanathan Subrahmanya, Chih-Ping Hsu
  • Patent number: 7330452
    Abstract: Techniques for inter-frequency neighbor list searching are disclosed. Embodiments disclosed herein address the need for inter-frequency neighbor list searching. In one embodiment, a searcher is deployed to search a PN space with a first set of search parameters and to return search results. A subset of those results are selected, along with a previously saved search result, to form a set of PN locations for a second search. The second search is performed on a window around each of the PN locations, using a second set of search parameters. The maximum peak from the second search is saved for use in future iterations. In one embodiment, the subset is selected as the highest energy level peaks from the first search. In one embodiment, if a maximum peak is deemed to correspond to a valid base station when the position of that maximum peak is within a pre-determined time offset from a previous maximum peak.
    Type: Grant
    Filed: June 13, 2003
    Date of Patent: February 12, 2008
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Thomas B. Wilborn, Roland Rick, Srinivasa Rao Nagaram, Chalapathi Rao Emani, Ramachandran Gurumoorthy, Jesus Chao, Steve Doerfler, Peter Ang, Srividya Kunisetti, Gwang-Hyun Gho, Thomas Bailey
  • Publication number: 20070298739
    Abstract: Techniques for segmented CDMA searching are disclosed. In one aspect, a searcher comprises a plurality of storage elements selectable for performing a plurality of segmentable search tasks, each storage element operable for storage of and access to state information for one of the plurality of search tasks. In another aspect, a first search task is interrupted in progress, the state information for the first task is stored, a second search task is performed, and the first search task is continued using the stored state information. In yet another aspect, a search task is segmented into smaller search segments, sized to fit within contiguous available time in the searcher. Various other aspects of the invention are also presented. These aspects have the benefit of circuit area and search-time efficiency which translate into reduced costs, increased standby time, increased acquisition speed, higher quality signal transmission, increased data throughput, decreased power, and improved overall system capacity.
    Type: Application
    Filed: May 8, 2007
    Publication date: December 27, 2007
    Applicant: QUALCOMM Incorporated
    Inventors: Subramanya Rao, Da-Shan Shiu, Jeremy Lin, Jeong Kim
  • Patent number: 7307480
    Abstract: Techniques for improved low latency frequency switching are disclosed. In one embodiment, a controller receives a frequency switch command and generates a frequency switch signal at a time determined in accordance with a system timer. In another embodiment, gain calibration is initiated subsequent to the frequency switch signal delayed by the expected frequency synthesizer settling time. In yet another embodiment, DC cancellation control and gain control are iterated to perform gain calibration, with signaling to control the iterations without need for processor intervention. Various other embodiments are also presented. Aspects of the embodiments disclosed may yield the benefit of reducing latency during frequency switching, allowing for increased measurements at alternate frequencies, reduced time spent on alternate frequencies, and the capacity and throughput improvements that follow from minimization of disruption of an active communication session and improved neighbor selection.
    Type: Grant
    Filed: April 24, 2003
    Date of Patent: December 11, 2007
    Assignee: QUALCOMM Incorporated
    Inventors: Da-shan Shiu, Li Zhang, Eugene Sy
  • Publication number: 20070230544
    Abstract: Techniques to filter pilot symbols for a pilot in an “adaptive” manner to provide an improved estimate of the response of a communication channel. A received signal may experience different channel conditions at different times, and different multipaths may also experience different channel conditions even when received close in time. A pilot filter with an adaptive response is used to provide an improved estimate of the channel response. Various adaptive pilot filtering schemes may be used. In a first scheme, the channel conditions are estimated based on the quality of the received pilot. In a second scheme, the channel conditions are estimated based on the quality of the pilot estimates (i.e., the filtered pilot symbols). For each scheme, a particular filter response is selected based on the estimated quality of either the received pilot or the pilot estimates.
    Type: Application
    Filed: June 11, 2007
    Publication date: October 4, 2007
    Applicant: QUALCOMM INCORPORATED
    Inventors: Parvathanathan Subrahmanya, Da-shan Shiu, Avneesh Agrawal
  • Publication number: 20070218935
    Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.
    Type: Application
    Filed: May 18, 2007
    Publication date: September 20, 2007
    Applicant: QUALCOMM INCORPORATED
    Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
  • Patent number: 7254170
    Abstract: Noise measurements are made within a fraction of a single symbol period of a longest orthogonal code symbol. A control processor identifies an unoccupied code having a spreading factor that is less than a longest spreading factor for the system. A despreader measures symbol energy based on the unoccupied code and a noise estimator generates noise estimations based on the measured symbol energies. The subscriber station uses similar techniques in order to perform channel estimations within a period that is a fraction of a symbol period of a longest-spreading-factor code.
    Type: Grant
    Filed: November 7, 2002
    Date of Patent: August 7, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Da-shan Shiu, Durga P. Malladi, Srikrishna Bhashyam
  • Patent number: 7251467
    Abstract: Systems and techniques are disclosed relating to wireless communications. These systems and techniques involve wireless communications wherein a device may be configured to recover an information signal from a carrier using a reference signal, detect a frequency error in the information signal; and periodically tune the reference signal to reduce the frequency error.
    Type: Grant
    Filed: October 14, 2003
    Date of Patent: July 31, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Andrew Sendonaris, Da-shan Shiu, Dominic Gerard Farmer, Jeremy H. Lin, Parvathanathan Subrahmanya, Thomas K. Rowland
  • Patent number: 7230975
    Abstract: Techniques to filter pilot symbols for a pilot in an “adaptive” manner to provide an improved estimate of the response of a communication channel. A received signal may experience different channel conditions at different times, and different multipaths may also experience different channel conditions even when received close in time. A pilot filter with an adaptive response is used to provide an improved estimate of the channel response. Various adaptive pilot filtering schemes may be used. In a first scheme, the channel conditions are estimated based on the quality of the received pilot. In a second scheme, the channel conditions are estimated based on the quality of the pilot estimates (i.e., the filtered pilot symbols). For each scheme, a particular filter response is selected based on the estimated quality of either the received pilot or the pilot estimates.
    Type: Grant
    Filed: August 7, 2001
    Date of Patent: June 12, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Parvathanathan Subrahmanya, Da-shan Shiu, Avneesh Agrawal
  • Patent number: 7215935
    Abstract: Techniques for segmented CDMA searching are disclosed. In one aspect, a searcher comprises a plurality of storage elements selectable for performing a plurality of segmentable search tasks, each storage element operable for storage of and access to state information for one of the plurality of search tasks. In another aspect, a first search task is interrupted in progress, the state information for the first task is stored, a second search task is performed, and the first search task is continued using the stored state information. In yet another aspect, a search task is segmented into smaller search segments, sized to fit within contiguous available time in the searcher. Various other aspects of the invention are also presented. These aspects have the benefit of circuit area and search-time efficiency which translate into reduced costs, increased standby time, increased acquisition speed, higher quality signal transmission, increased data throughput, decreased power, and improved overall system capacity.
    Type: Grant
    Filed: January 17, 2002
    Date of Patent: May 8, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Subramanya P. Rao, Da-shan Shiu, Jeremy H. Lin, Jeong Geun Kim
  • Patent number: 7190750
    Abstract: Techniques for tracking closely spaced multipath and preventing finger merge without monitoring relative positions between each of a plurality of fingers are disclosed. In one aspect, motion limits are determined for each finger. Time-tracking commands that would move the position of a finger outside its respective motion limits are suppressed. In another aspect, motion limits are updated dynamically, the motion limits of each finger determined in accordance with the motion limits of fingers adjacent to it. Various other aspects are also presented. These aspects have the benefit of preventing finger merge, which allows the allocation of multiple fingers to closely spaced multipath, thus increasing performance and system capacity, and mitigating misallocation of system resources.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: March 13, 2007
    Assignee: Qualcomm Incorporated
    Inventors: Edward Harrison Teague, Messay Amerga, Jeremy Lin, Da-shan Shiu
  • Patent number: 7187708
    Abstract: A buffer structure for storing symbols received via a number of (e.g., physical or transport) channels. Each channel is associated with a particular time interval (e.g., a radio frame period or a transmission time interval (TTI)) over which the received symbols are processed (e.g., interleaved). The buffer structure includes a buffer and an address generator. The buffer is partitioned into a number of sections. One section is assigned to each channel being processed. Each section can be operated as a circular buffer. The address generator provides addresses for writing symbols to the assigned sections. If the buffer structure is used for the transport channels, the sections can be assigned to the transport channels based on the associated TTIs (e.g., in descending order of TTIs). For each coded composite transport channel (CCTrCH), the transport channels in the CCTrCH can be assigned to sections defined starting from a respective initial location (e.g.
    Type: Grant
    Filed: October 3, 2000
    Date of Patent: March 6, 2007
    Assignee: Qualcomm Inc.
    Inventors: Da-Shan Shiu, Avneesh Agrawal
  • Patent number: 7155177
    Abstract: Techniques for predicting weights used for closed-loop transmit diversity. In a channel prediction scheme, channel gains for multiple transmit antennas are initially estimated (e.g., based on pilots received from these antennas) and used to derive predicted channel gains for a future time instant. The predicted channel gains are then used to derive predicted weights that are deemed to be “optimal” at the future time instant. Optimality may be determined based on one or more criteria, such as maximizing a received SNR for the received signals. In a weight prediction scheme, the channel gains for the multiple antennas are estimated and used to compute optimal weights for the current time instant. The current optimal weights are then used to predict the optimal weights at the future time instant. For both schemes, the prediction may be performed based on an adaptive filter (e.g., LMS or RLS filter) or a non-adaptive filter.
    Type: Grant
    Filed: February 10, 2003
    Date of Patent: December 26, 2006
    Assignee: Qualcomm Incorporated
    Inventors: Jittra Jootar, Da-shan Shiu, Parvathanathan Subrahmanya
  • Publication number: 20060189342
    Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.
    Type: Application
    Filed: November 1, 2005
    Publication date: August 24, 2006
    Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
  • Patent number: 7089030
    Abstract: Systems and techniques are disclosed relating to communications. The systems and techniques involve transmitting to a remote location a first signal at a first energy level followed by a second signal at a second energy level, determining a target transmission energy level as a function of a target quality parameter at the remote location, and computing the second energy level as a function of the target transmission energy level and the first energy level. It is emphasized that this abstract is provided solely to assist a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: August 8, 2006
    Assignee: QUALCOMM Incorporated
    Inventors: Alkinoos Hector Vayanos, Durga Prasad Malladi, Da-shan Shiu
  • Patent number: 7010321
    Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.
    Type: Grant
    Filed: February 4, 2002
    Date of Patent: March 7, 2006
    Assignee: Qualcomm Inc.
    Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
  • Publication number: 20060040698
    Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified- for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.
    Type: Application
    Filed: October 12, 2005
    Publication date: February 23, 2006
    Inventors: Da-shan Shiu, Serge Willenegger, Richard Chi, Parvathanathan Subrahmanya, Chih-Ping Hsu
  • Patent number: 6983166
    Abstract: Techniques to more efficiently control the transmit power for a data transmission that uses a number of formats (e.g., rates, transport formats). Different formats for a given data channel (e.g., transport channel) may require different target SNIRs to achieved a particular BLER. In one aspect, individual target BLER may be specified for each format of each data channel. In another aspect, various power control schemes are provided to achieve different target SNIRs for different formats. In a first power control scheme, multiple individual outer loops are maintained for multiple formats. For each format, its associated outer loop attempts to set the target SNIR such that the target BLER specified for that format is achieved. In a second power control scheme, multiple individual outer loops are maintained and the base station further applies different adjustments to the transmit power levels for different formats.
    Type: Grant
    Filed: August 20, 2001
    Date of Patent: January 3, 2006
    Assignee: Qualcomm, Incorporated
    Inventors: Da-shan Shiu, Serge Willenegger, Richard Chi, Parvathanathan Subrahmanya, Chih-Ping Hsu